This project would experimentally evaluate a comprehensive, low-cost intervention involving parent and teacher training in child behavior management and child training in social skills to reduce early conduct problems, one of the major predictors of later drug abuse. By using programs that build on and complement each other, the intervention is designed to maximize the benefits of ensuring a consistent approach between home and school. In addition, by using a low-cost and easily implemented intervention, the likelihood that the intervention could be replicated widely is maximized. One-hundred and eighty children exhibiting high levels of conduct problems in kindergarten will be randomly assigned to an intervention or control classroom in first grade. Additionally, 120 teachers will be randomly assigned to receive intensive training in classroom management strategies and in implementing a classroom social skills program, or to serve as a one- year wait-list control. Teachers assigned to immediate intervention will receive six days of video-based group training in effective classroom management strategies Additionally, these teachers will implement a video-based classroom-wide social problem-solving and social skills program. Parents of the participating children assigned to intervention classrooms will also receive a video-based self- administered parent training program and brief consultation with a therapist. Outcome analyses will primarily focus on children's conduct problems and teachers' behaviors, and secondarily on children's social skills, school records, and utilization of medical and psychological services. In addition, a longitudinal model of the prediction of conduct problems at school and (in potential renewals of this project) of drug abuse itself will be tested, including in the model child factors such as early conduct problems, attention problems, reading ability, and social skills, and contextual variables such as parenting skill and teacher use of positive reinforcement and effective discipline. Finally, cost-benefit analyses of the intervention will also be performed.